This invention relates to dual wheel structures on vehicles, such as those found on tractor-trailers, and more particularly to a valve extension support for use in dual wheel applications that dampens vibration of a valve extension attached to the inflation valve of the inner dual wheel.
In wheel applications where wheels are dualled on an axle, it is often necessary to increase the length of the inflation valve associated with the inner wheel so that it can be more easily accessed from the outside of the vehicle to allow for proper monitoring and adjustment of the inner tire""s air pressure. The most common method for lengthening the inflation valve is to use an inflation valve extension. Typically, the inflation valve extension takes the form of a small diameter metal tubular device that attaches to the end of the inflation valve of the inner wheel and extends outward through a vent hole in the outer wheel.
Unfortunately, the weight of the inflation valve extension, coupled with the high rotational speeds of wheels in service, increases the vibration magnitude and stress on the inner wheel""s inflation valve during service. This leads to fatigue cracks in the inflation valve, often resulting in a loss of tire pressure that may in turn lead to tire damage and/or poor fuel economy.
Hence, there is a need for a device that can be used to dampen the vibration of an inflation valve fitted with a valve extension installed on an inner dual wheel. Preferably, the device should fit various wheel designs, be easily installed and removed, remain secured after installation, be lightweight, allow access to the end of the inflation valve assembly, and be resistant to a variety of environmental conditions.
A valve extension support of the present invention may be used with dualled wheels, where the outer wheel has a vent hole that the valve extension protrudes through. The valve extension support includes a deformable substantially cylindrical main body formed from elastomeric foam material and having inboard and outboard ends. The valve extension support is deformable between three states: an undeformed state, an installed state, and an installation state. The main body has a cross-sectional dimension larger than the vent hole in the undeformed state, but is deformable to be disposed through the vent hole in the installed state. The main body has an associated outboard retention flange at or towards one end, and an associated inboard retention flange at or towards the other end. The outboard flange has a plan view cross-sectional dimension larger than the vent hole in the undeformed and installed states. The inboard retention flange has a cross-sectional dimension larger than the vent hole in the undeformed state and in the installed state, but may be deformed to be smaller than the vent hole in the insertion state. In this manner, the valve extension support may be inserted into the vent hole, and remains deformed while in the vent hole. The main body has a passage passing therethrough that is adapted to grip the valve extension in the installed state due to the deformation of the main body from being xe2x80x9csqueezedxe2x80x9d in the vent hole.
Once installed, the inboard and outboard retention flanges are disposed on opposite sides of the outboard wheel. The two retention flanges are preferably spaced such that the outboard wheel is not laterally squeezed between the flanges, thereby allowing the valve extension support to be easily oriented in a variety of positions relative to the vent hole. The two retention flanges may be substantially identical, or may be different. There may be an optional valve end recess on one or both sides of the valve extension support to provide clearance for monitoring air pressure.
With the retention flanges on both ends of the valve extension support, the valve extension support device is safely retained in the vent hole, such that vibration and motion of the wheel in normal operation should not cause the valve extension support to become dislodged from the outboard wheel. The interference compression fit of the valve extension support device in the vent hole also prevents it from becoming dislodged is service.
The valve extension support device can be removed by pushing or pulling it out of the vent hole. Sufficient force must be exerted to overcome the interference fit and collapse the appropriate retention flange.
The valve extension support should be made from a low density elastomeric foam material, preferably of a heat resistant closed cell type with ultraviolet light and ozone inhibitors.